1. Field of the Invention
This invention relates to a resin composition, and more particularly to a resin composition comprising a polyphenylene ether resin and a polyolefin resin as its main ingredients and having enhanced mechanical properties, particularly impact resistance.
2. Description of the Prior Art
Polyphenylene ether resin is useful because of its excellent mechanical and electrical properties and high heat resistance. However, it has a fault that it is inferior in moldability and solvent resistance, due to which the use of polyphenylene ether resin itself is greatly restricted.
On the other hand, polyolefin resins and particularly crystalline polyolefin resins are characterized by their low density and inexpensiveness, in addition to their excellence in moldability and solvent resistance, owing to which they are widely used practically as molded articles and films. However, such polyolefin resins have a fault that they are poor in heat resistance, and this fault greatly obstructs a further expansion of their use.
Under such a situation, it is industrially valuable to blend together a polyphenylene ether resin and a polyolefin resin, both having respective excellent characteristic features, to prepare a resin composition having the advantageous points of both the resins. Thus, resin compositions comprising a polyolefin resin and a polyphenylene ether resin have already been proposed in Japanese Patent Application Kokoku (Post. Exam.) No. 42-7069, Japanese Patent Application Kokai (Laid-Open) No. 2-115248, etc.
Generally speaking, however, polyphenylene ether resin and polyolefin resin are low in mutual affinity, and a sufficiently compatible mixture cannot be prepared by merely blending them together.
As resin compositions overcoming such a fault, there have been proposed a resin composition containing an acid-modified polyolefin resin and a polyphenylene ether resin (Japanese Patent Application Kokai (Laid-Open) No. 60-120748), a resin composition comprising a modified polyolefin resin and a modified polyphenylene ether resin (Japanese Patent Application Kokai (Laid-Open) No. 63-128056), etc.
In these resin compositions so far proposed, however, compatibility is insufficient, and their mechanical properties such as impact resistance are unsatisfactory, even though they are improved in solvent resistance, moldability, etc.